Amnesia after diazepam infusion into basolateral but not central amygdala of Rattus norvegicus

Recent findings indicate that the memory-impairing effects of benzodiazepines may preferentially involve the basolateral nucleus of the amygdala. To test this hypothesis we examined the effects on pretrial injection of diazepam into the central as compared to the lateral/basolateral amygdaloid nuclei on memory for a conditioned avoidance response. Rats were implanted bilaterally with cannulae directed to either the central or lateral/basolateral amygdaloid nuclei. Five to 7 days later they were trained on a multitrial inhibitory avoidance (step-down) task to criterion and tested 48 h later. Fifteen minutes before training they were given an injection of either vehicle or diazepam (0.7 or 1.4 nmol) into the central or lateral/basolateral nuclei. Administration of diazepam into the lateral/basolateral nuclei but not the central nucleus induced anterograde amnesia. These results add to the body of data linking the GABA-benzodiazepine system of the lateral/basolateral nuclei to the amnestic effects induced by peripheral as well as central administration of benzodiazepines.